docs: fix typo in bihash clib_bihash_search() documentation

Type: docs

Change-Id: Ic8c628141f8a24b857a654e2ea9129f5f97807b6
Signed-off-by: Jon Loeliger <jdl@netgate.com>

docs/gettingstarted/developers/bihash.md

@@ -201,9 +201,9 @@ The simplest possible (key, value) search goes like so:
    search_kv.key = key_to_add_or_delete;
 
    if (clib_bihash_search_8_8 (h, &search_kv, &return_kv) < 0)
-     key_not_found()
-   else
      key_not_found();
+   else
+     key_found();
 ```
 
 Note that it's perfectly fine to collect the lookup result